The present invention relates to a printer, and more particularly, to a printer used in, for example, an electronic typewriter.
Conventionally, in an apparatus such as an electronic typewriter which carries out printing by typing, a type wheel is, for example, employed in which type faces of the same standardized size are respectively arranged around heads of a support shaped into a form of a vane wheel. This type wheel is driven by a wheel motor so that a type face to be used in printing is led to a printing position. The type wheel is then struck by a printing hammer. Then the type face presses an ink ribbon against a paper or the like to thereby carry out printing.
In printing, if type faces having different contact areas with an ink ribbon, for example, "W" and "." are struck completely in the same way, they are printed differently. Namely, "." is printed more densely than "W". In order to avoid such a problem, the working speed of a printing hammer is controlled according to type faces. In particular, the speed is fast when striking a type face with a large contact area with the ink ribbon (for example, "W"), and is slow when striking a type face with a small contact area with the ink ribbon (for example, ".").
In the conventional printer described above, time to select the next type face to be struck by driving the type wheel is based on the time taken to strike the type face with the smallest contact area with the ink ribbon (that is, when the working speed of the printing hammer is the slowest, and the time taken for striking is the longest). In this apparatus, when a type with a large contact area with the ink ribbon is printed, the latency time till the next type is selected is long, which causes a reduction in printing speed.